code: def test_one_reduction_op(self, xp):
      return lambda x, y: xp.sum(x, axis=0)
  
imports: import unittest
  from unittest import mock
  import cupy
  from cupy import testing
  from cupy_tests.core_tests.fusion_tests import fusion_utils
label_desc: Use image node_id 15 for calling the TestOptimizations obj's underlying member method code with example usage: obj.test_one_reduction_op(xp) and returns: function